1. Field
Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to methods and apparatus of monitoring radio channels.
2. Background
Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSPA), which provides higher data transfer speeds and capacity to associated UMTS networks.
In UMTS, a wireless communication device, referred to as a user equipment (UE), regularly searches for a better cell to camp on according to a cell reselection criterion. This mechanism insures an acceptable quality of the camping cell, and achieves a desired call setup performance or power savings. For example, a very reactive cell reselection mechanism can guarantee an adequate quality of the camping cell at the expenses of stand-by time, which is decreased by frequent reselections.
Therefore, improved cell reselection mechanisms are desired.